Poke the sweet potato all over with a fork. Wrap the potato in wax paper and place on a microwavable plate. Microwave the potato approximately 8 to 12 minutes(depending on your microwave)until fork tender. Remove the sweet potato from the microwave, unwrap and let stand until cool enough to handle. Cut the potato in half lengthwise and scoop out 1 cup of the flesh into a small bowl. Cool completely.

Preheat the oven to 425 degrees. Line a large sheet pan with parchment paper. Blend together the 1 1/3 cups flour, cornmeal, baking powder and salt in a food processor. Add the butter and pulse until coarse crumbs form. Add the sweet potato flesh, buttermilk and syrup and process until well blended. Add the pecans and pulse to blend. Gather up the dough and transfer to a floured surface. Sprinkle the dough with additional flour and pat out into an 8 inch square. Cut out biscuits with a floured biscuit cutter. Transfer the biscuits to the prepared pan. Gather up the dough scraps, pat out and cut additional biscuits. Bake the biscuits about 18 to 22 minutes until a toothpick comes out clean. Serve the sweet potato biscuits warm.